I don't get this dew point/glycerin thing at all, despite reading several articles about it. I mean, I understand the basic science, but my hair doesn't seem to follow it. The dew point can be "optimal" but if the humidity is high, my hair will still be frizzier than usual. Optimal for me seems to be dry/arid, which is not supposed to be "optimal." And it doesn't seem to make a difference when I use products with glycerin in them (my hair hates a high glycerin content on dry hair though), what seems to make a difference is how humid it is. I revisit noting the dew point and trying to apply product accordingly but humidity seems to be what makes a difference. Shrug. Glad knowing the dew point works for many curlies though.